Barrier walls that are formed from a plurality of elongated piles typically are driven into the earth to a depth sufficient to support the piles in an upright attitude. In some cases, the piles are in the form of extruded structural panels and are formed with male and female opposed edges so that similar panels can be locked together at their adjacent edges to form a continuous barrier wall. Because of the strength required of the structural panels when being driven into the earth and the strength required under load conditions, the panels have often been made of steel or aluminum. Although various methods exist to protect the steel and aluminum panels from the environment, such as using coatings or layers of paint, steel and aluminum panels have the tendency to suffer from corrosion, especially when used in aquatic environments. As well, steel and aluminum panels are relatively expensive to produce and heavy, which hinders installation operations.
In recent years, structural panels have been constructed of polyvinyl chloride and other plastics in order to reduce their weight and susceptibility to corrosion. However, these plastics have relatively low tensile and high compression strengths as compared to steel. To help maintain the structural panels in the desired positions, horizontally mounted structural elements, such as wales, are mounted along the outer surfaces of the structural panels and tie rods extend from the wale elements back through the panels to a force abutter disposed behind the barrier wall. Typically, the force abutter is a reinforced cement wall disposed a desired distance behind the barrier wall such that adequate retaining force is exerted from the force abutter through the tie rods against the barrier wall, thereby maintaining the barrier wall in the desired position. Instead of using a force abutter for several tie rods, individual ground anchors may be used with each tie rod. Typically, the wale elements that have been used to stabilize a retaining wall were comprised of wood. The use of wood in the wales risks significant damage from both exposure to the environment as well as from infestation of the wood elements by wood borers and other insects and organisms. Wale elements also have been comprised of steel and other metals which are susceptible to corrosion when used in aquatic environments such as those that exist near sea walls. Although the steel wale elements can be protected by coatings, these coatings must be breached when passing tie rods through the wale elements to the force abutter disposed behind the barrier wall. The points at which the protective coatings are breached leave the steel wale elements subject to corrosion. Preferably, the life cycles of the various components (wales, piles, anchor system, etc.) are each maximized in that replacement of one component often requires great effort and expense, even though the remaining components still perform adequately.
Existing wales tend to have square or rectangular cross-sections, meaning the bottom face of the wale is perpendicular to the wall. Therefore, when the wall is used as a sea wall, the bottom face of the wale can pose a threat to watercraft (boats, barges, etc.) in that portions of the watercraft can become caught underneath the wale due to wave action and/or tidal shifts. This not only can cause physical damage (scrapes, punctures, etc.), but restricting the free motion of the watercraft can pose stability problems. As well, force created wave action against the bottom face of the wale can affect the structural integrity of the sea wall over time.
Therefore, there is a need for improved structural members which address these and other shortcomings of the prior art.